1 files changed, 141 insertions, 0 deletions
diff --git a/layout/style/Rule.h b/layout/style/Rule.h
new file mode 100644
index 0000000000..a3ff02414e
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+++ b/layout/style/Rule.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* base class for all rule types in a CSS style sheet */
+
+#ifndef mozilla_css_Rule_h___
+#define mozilla_css_Rule_h___
+
+#include "mozilla/dom/CSSRuleBinding.h"
+#include "mozilla/dom/DocumentOrShadowRoot.h"
+#include "mozilla/StyleSheet.h"
+#include "mozilla/MemoryReporting.h"
+#include "nsISupports.h"
+#include "nsWrapperCache.h"
+
+template <class T>
+struct already_AddRefed;
+
+namespace mozilla {
+
+enum class StyleCssRuleType : uint8_t;
+
+namespace css {
+class GroupRule;
+
+class Rule : public nsISupports, public nsWrapperCache {
+ protected:
+  Rule(StyleSheet* aSheet, Rule* aParentRule, uint32_t aLineNumber,
+       uint32_t aColumnNumber)
+      : mSheet(aSheet),
+        mParentRule(aParentRule),
+        mLineNumber(aLineNumber),
+        mColumnNumber(aColumnNumber) {
+#ifdef DEBUG
+    AssertParentRuleType();
+#endif
+  }
+
+#ifdef DEBUG
+  void AssertParentRuleType();
+#endif
+
+  Rule(const Rule& aCopy)
+      : mSheet(aCopy.mSheet),
+        mParentRule(aCopy.mParentRule),
+        mLineNumber(aCopy.mLineNumber),
+        mColumnNumber(aCopy.mColumnNumber) {}
+
+  virtual ~Rule() = default;
+
+ public:
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_SKIPPABLE_WRAPPERCACHE_CLASS(Rule)
+  // Return true if this rule is known to be a cycle collection leaf, in the
+  // sense that it doesn't have any outgoing owning edges.
+  virtual bool IsCCLeaf() const MOZ_MUST_OVERRIDE;
+
+  virtual bool IsGroupRule() const { return false; }
+
+#ifdef DEBUG
+  virtual void List(FILE* out = stdout, int32_t aIndent = 0) const = 0;
+#endif
+
+  StyleSheet* GetStyleSheet() const { return mSheet; }
+
+  // Clear the mSheet pointer on this rule and descendants.
+  virtual void DropSheetReference();
+
+  // Clear the mParentRule pointer on this rule.
+  void DropParentRuleReference() { mParentRule = nullptr; }
+
+  void DropReferences() {
+    DropSheetReference();
+    DropParentRuleReference();
+  }
+
+  uint32_t GetLineNumber() const { return mLineNumber; }
+  uint32_t GetColumnNumber() const { return mColumnNumber; }
+
+  // Whether this a rule in a read only style sheet.
+  bool IsReadOnly() const;
+
+  // Whether this rule is an @import rule that hasn't loaded yet (and thus
+  // doesn't affect the style of the page).
+  bool IsIncompleteImportRule() const;
+
+  // This is pure virtual because all of Rule's data members are non-owning and
+  // thus measured elsewhere.
+  virtual size_t SizeOfIncludingThis(MallocSizeOf) const MOZ_MUST_OVERRIDE = 0;
+
+  virtual StyleCssRuleType Type() const = 0;
+
+  // WebIDL interface
+  uint16_t TypeForBindings() const {
+    auto type = uint16_t(Type());
+    // Per https://drafts.csswg.org/cssom/#dom-cssrule-type for constants > 15
+    // we return 0.
+    return type > 15 ? 0 : type;
+  }
+  virtual void GetCssText(nsACString& aCssText) const = 0;
+  void SetCssText(const nsACString& aCssText);
+  Rule* GetParentRule() const;
+  StyleSheet* GetParentStyleSheet() const { return GetStyleSheet(); }
+  nsINode* GetAssociatedDocumentOrShadowRoot() const {
+    if (!mSheet) {
+      return nullptr;
+    }
+    auto* associated = mSheet->GetAssociatedDocumentOrShadowRoot();
+    return associated ? &associated->AsNode() : nullptr;
+  }
+  nsISupports* GetParentObject() const { return mSheet; }
+
+ protected:
+  // True if we're known-live for cycle collection purposes.
+  bool IsKnownLive() const;
+
+  // Hook subclasses can use to properly unlink the nsWrapperCache of
+  // their declarations.
+  void UnlinkDeclarationWrapper(nsWrapperCache& aDecl);
+
+  // mSheet should only ever be null when we create a synthetic CSSFontFaceRule
+  // for an InspectorFontFace.
+  //
+  // mSheet and mParentRule will be cleared when they are detached from the
+  // parent object, either because the rule is removed or the parent is
+  // destroyed.
+  StyleSheet* MOZ_NON_OWNING_REF mSheet;
+  Rule* MOZ_NON_OWNING_REF mParentRule;
+
+  // Keep the same type so that MSVC packs them.
+  uint32_t mLineNumber;
+  uint32_t mColumnNumber;
+};
+
+}  // namespace css
+}  // namespace mozilla
+
+#endif /* mozilla_css_Rule_h___ */